Leak-proof closure for a liquid container

ABSTRACT

A leak-proof closure for a liquid container having a threaded neck. A cap for the closure has internal threads which mate with those on the container neck. The cap has an annular skirt portion above or below the threaded section. The container neck has at least one annular sealing ring on its outer surface at such a level that the cap skirt portion fits circumjacent the ring when the cap is threaded onto the neck into closed position. The outer diameter of the ring and the inner diameter of the cap skirt are such that an interference fit therebetween is established. Preferably the sealing ring or rings have a sharp edge in order to provide substantially a line contact with the skirt portion. In a preferred and illustrated embodiment, co-operating means are provided on the cap and the container to make the closure childproof.

United States Patent Montgomery July 30, 1974 [75] Inventor: Gary VanMontgomery, Evansville,

Ind.

[73] Assignee: Sunbeam Plastics Corporation,

Evansville, Ind.

[22] Filed: May 3, 1973 [21] Appl. No.: 356,913

[52] U.S. Cl. ...n u 215i? [51] Int. Cl. .mlj IITRLB6SdSO2 [58] Field ofSearch 215/40, 43, 9

[56] References Cited UNITED STATES PATENTS 3,679,084 7/1972 Aronson215/43 R 3,717,287 2/1973 Marand 215/9 Primary Examiner-George T. HallAttorney, Agent, or Firm-Henry K. Leonard [5 7] ABSTRACT A leak-proofclosure for a liquid container having a threaded neck. A cap for theclosure has internal threads which mate with those on the containerneck. The cap has an annular skirt portion above or below the threadedsection. The container neck has at least one annular sealing ring on itsouter surface at such a level that the cap skirt portion fitscircumjacent the ring when the cap is threaded onto the neck into closedposition. The outer diameter of the ring and the inner diameter of thecap skirt are such that an interference fit therebetween is established.Preferably the sealing ring or rings have a sharp edge in order toprovide substantially a line contact with the skirt portion. In apreferred and illustrated embodiment, co-

7 operating means are provided on the cap and the container to make theclosure child-proof.

11 Claims, 11 Drawing Figures mmmmamau SHEEF 2 BF 2 LEAK-PROOF CLOSUREFOR A LIQUID CONTAINER BACKGROUND OF THE INVENTION The use of threadedcaps or caps having bayonet type lugs for liquid containers is, ofcourse, wide spread and, in order to close such containers tightly, itis necessary to provide a liner positioned in the interior of the capand which is tightened against the end of the container neck to seal thecontainer. Thin disks of cork have frequently been used for this purposein the past because of the high resiliency of the cork which enables itto withstand sealing pressures of varying types without tanking a set".In a threaded container, if the liner takes a set, the cap must beturned on to the container a greater distance with each successiveremoval and replacement in order to seal the container. In a bayonettype the liner may gradually be compressed beyond sealing thickness and,of course, cannot be sealed against leakage. if it has taken .a set.

In more recent years, because the price of cork has risen soastronomically, substitute materials such as plastic foams or the likehave been used for fabricating liners for threaded and other types ofcontainer caps but most of the substitute materials are less resilientthan cork and, in many instances, they do take a set which means thatthe containermay leak after continued use. i

The problem resulting from the lack of resiliency of the substitutematerials is even more severe when the means for retaining the cap onthe container neck are not threads'but are bayonet-type lugs and lugsthreads or similar means which have only one closed position, i.e. whichcannot be tightened on to the container a little more in successivereplacements to compensate for the set or less thickness of the linerresulting from repeated use. i

The same problem exists when a cap is initially placed on a containerneck by automatic capping machines which place the cap on the neck, evenif threaded, with a certain predetermined torque which may or may not begreater or less than the torque applied to the cap by a user who isreplacing the cap.

Even greater problems exist when a cap of the so i called child-proof"or safety type is utilized and the cap is threaded on to the containerbeyond its position wherein it is rendered difficult of removal. When achild is attempting to remove a cap of this type it may be able to turnit, for example, to the child-proof position, and while the child cannotremove the cap, this will reduce the pressure on the liner. If the linerhas been squeezed more tightly during a capping procedure, and if it isof a material that will take a set, the partial loosening of the cap bythe child seeking to remove the cap, may destroy its leak-proof abilityand result in the container leaking even though the child has beenunable to remove the cap.

It is, therefore, the principalobject of the instant invention toprovide a leak-proof closure for a liquid container comprising a caphaving auxiliary means which cooperate with means on the container neckto continue the cap as leak-proof even though it may be loosenedsomewhat.

It is another object of the instant invention to provide a closure for aliquid container which can be equipped with an inexpensive cap liner,the closure comprising co-operating means on the container neck and thecap which maintain the closure leak-proof even after the liner has beencompressed to a degree beyond its normal thickness, thus compensatingfor unequal capping pressures or the tendency of the liner to take aset.

the cap from thevcontainer; the cap and the container neck havingcooperating means which maintain the closure in leak-proof conditioneven though it may be retracted slightly from its initial closedposition.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a fragmentary, diametric,vertical, sectional view of a closure embodying the invention'asutilized on a child-proof closure-embodying Gach and LeonardApplication, Ser. No. 278,l01, filed Aug. 4, 1972 now US Pat. No.3,770,153;

FIG. 2 is a horizontal, partly plan and partly sectional view, takenalong the line 2-2 of FIG. 1;

FIG. 3 is a horizontal sectional view taken along the line 3-3 of FIG.1;

FIG. 4 is a vertical, diametric, sectional view of a cap according tothe invention;

FIG. 5 is a fragmentary view in side elevation of a closure embodyingthe invention, the interior parts being shown in phantom;

FIG. 6 is a fragmentary, isometric view of a container neck embodyingthe invention as provided with means cooperating with the cap shown inFIG. 4 to render'the closure leak-proof;

FIG. 7 is a fragmentary, vertical sectional view of a modified form ofclosureembodying the invention;

FIG.- 8 is a view similar to FIG. 6 but of the neck of the containeralso shown in FIG. 7;

FIG. 9 is a view similar to FIG. 7 but showing a third modificationof'the'inven'tion;

FIG. 10 is a view similar to FIG. 8 but of the neck of the, containeralso shown in' FIG. 9; and

FIG. 11 is a view similar to FIGS. 7 and 9 and showing yet anothermodification of the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS A closure embodying the inventionis designed for a container, generally indicated by the reference number10, having a neck 11 to be closed by an inverted cupshaped cap 12.

In the embodiment of the invention illustrated in FIGS. l-6, thecontainer neck 11 and the cap 12 have cooperating disengageable meansfor retaining the cap 12 on the container 10 which consist of externalthreads 13 on the container neck 11 and internal threads 14 on the innerside of a cap skirt l5. The cap 12 also has an interior liner 16 whichis squeezed tightly against the end of the neck 11 when the cap 12 is onthe container in closed position as illustrated in FIG. 1.

The cap 12 has a depending skirt portion 17 which extends downwardlybeyond its threads 14 and fits closely circumjacent to one or moresealing rings 18 provided on the exterior of the container neck 11 at alevel below its threads 13. The outer diameter of the sealing rings 18and the inner diameter of the cap skirt which in this case, issubstantially a line contact between the sealing ring or rings 18 andthe skirt portion 17, much in the fashion of a O-ring. Preferably thesealing rings 18 have sharp edges so as to maintain the line'contact. 1

If the cap 12 is threaded onto the container neck 11 with considerabletorque'so that it squeezes the cap liner 16 tightly against the end ofthe container neck 1 1, either upon initial capping of the container orupon subsequent replacement of the cap 12, the person replacing the cap12 may not turn it downwardlyon the neck 11' as tightly as it wasinitially closed. In the event that the cap liner 16 takes a set as aresult of the ini tial closing, a subsequent replacement of the cap maynot turn it down tightly enough to reseal the end of the neck 11 againstleaking. In the event of this'common occurrence, liquid contents of thecontainer may leakbecause the compressed liner 16 no longer functionsfor its intended purpose; If such event occurs, the contents of thecontainer may leak from the container into the interior of the cap 12.However, because of the contact provided by the sealingrings 18 engagingthe cap skirt portion 17, this material will not actually leak fromthe'closure. v

The advantage accruing from the cooperating ring and annular skirtportion according to the invention also is important upon initialcapping of the container on the production line of the establishment atwhich liquid containers are filled.

Normal industry tolerances in the manufacture of containers, caps andliners are such that a cap placed on a container might co'mpress theliner as much as 0.020 inches beyond nominal or as much as 0.020 inchless than nominal. For example, in a screw type closure having a sixpitch thread (6 threads per inch) the manufacturing tolerances of. thecontainer and c'apmay cumulate to result inasmuch as 80 of rotationbetween minimum or maximumThis would beplus or minus 40 fromnominalsealed position. Becasue each degree of rotation of the six pitchthread results in 0.0005 inch vertical movement, thus, 40 below nominalresults in the liner being compressed0020 inch beyond (thinner) thannominal or, on the other hand, results in the liner only barelycontacting the bottle neck or not contacting it at all.

If the liner takes a set in the first instance, later replacement of thecap would result in a leak. If the cap is rotated to only to. 40short'of nominal, a leak may immediately result.

The leak-proof feature of a cap embodying the invention is particularlyuseful when the closure is of the socalled child-proof type, forexample, a closure such as that disclosed in the Gach and Leonardapplication. A closure of this type comprises a pair of dependinglocking lugs 19 on an outer cap skirt 20 which are engage able in twosquare ended recesses 21 formed in a shoulder 22 on the container 10.When this embodiment of the invention is threaded onto the containerneck 11,

the locking lugs 19 engage cams 23 on the shoulder 22' of the containerand are urged outwardly as the cap 12 is rotated to closed position,finally snapping into the recesses 21.

In order to remove a cap 12 thus designed, it is necessary to squeezethe outer cap skirt 20 inwardly on the two opposed sides indicated bythe open narrows in FIG. 3, thus to flex the lugs 19 outwardly asufficient distance to clear the square shoulders in the recesses 21whereupon the cap can be unscrewed in the usual fashion.

The cap structure according to the mentioned Gach and Leonardapplication has been proven to be substantially child-proof. However, ifthe cap is screwed onto the container to a degree such that the lockinglugs move any distance beyond the square shoulders of the cooperatingrecesses 21, the cap liner 16 may be compressed to a degree such that itwill not restore to its original thickness. If the liner 16 has thusbeen compressed, for example by the capping machine having turned thecap 12 too far onto the container neck 11, or by a subsequent adult whohas actuated the release mechanism and opened the cap and then turned itback onto the container neck 11 beyond the engagement of the lugs 19with recesses '11, when a child is endeavoring to remove the capbyturning it backwardly hewill not be able to turn it beyond theengagement of the lugs 19 with the recesses 21. However, by merelyturning it backward a sufficient distance to engage these cooperatingchild-proof elements, he may relieve the pressure on the liner 16 tosuch a degree that liquid material may leak out of the container 10 intothe interior of the cap 12. Again, the cooperation of the sealing rings18 with the inner skirt portion 17 of the cap 12 will prevent thecontents which may have leaked into the interior of the cap 12 fromleaking out of the container closure itself.

FIGS. 7 and 8 illustrate how a closure embodying the invention may bearranged so that one or more sealing rings 25 are located at the upperend of a container neck 26 for cooperation with an annular skirtportionthe cap 28, are illustrated in FIGS. 7and 8 as being the same type asthat shown in FIGS. 1-6, inclusive, with respect to the child-proofdesign of the cap,these features of child-proof construction are thesubject matter of the mentioned Gach and Leonard application and are notthe basic subject matter of the instant application. The combination ofsuch child-proof features with the leak-proof features of the instantinvention, however, does constitute an improvement over the mentionedGach and Leonard application.

A third embodiment of the invention is illustrated in FIGS. 9 and 10where a single sealing ring 30 is formed on a neck 3l of a bottle 32, orother container, at a level below the cap retaining means, i.e. bottleneck threads 33. As in the case of the embodiment of the inventionillustrated in FIGS. '1-6, a cap 34 as shown in FIG. 9 has an annularskirt portion 35 below its internal threads 36. The annularskirt-portion 35 and the flat,

In FIG. 11 a bottle or other container 37 has a neck 38 provided on itsouter surface with a plurality of undercut recesses 39 and axiallyextending slots 40. In this embodiment, four of the slots 40 and therecesses 39 are shown. At a level just below the bottoms of the recesses39, one or more sealing rings 41 are also formed on the exterior of thebottle neck 38. These rings may be substantially identical with therings 18 of FIGS. 1-6, or the rings 25 of FIGS. 7 and 8. Similarly, ofcourse, and if desired, instead of a plurality of rings 41 as shown inFIG. 11, a single cylindrical ring such as the ring 30 of FIG. 10 may beemployed with a bayonettype closure as shown in FIG. 11.

A cap 42 has a plurality of inwardly extending lugs 43 which are of suchsize and so positioned as to be movable downwardly through the slots 40and, when the cap 42 is rotated in a clockwise direction, to enter therecesses 39 to retain the cap 42 on the bottle 37. At this point, ofcourse, the sealing rings 41 engage the inner surface of an annularskirt portion 44 of the cap 42.

In common with the other illustrated embodiments of the invention, FIG.11 also shows how the child-proof feature of the mentioned Gach andLeonard application may be employed on a bayonet-type cap embodying theinstant invention.

Although threaded plastic caps have a tendency to back off as a resultof vibration during handling and shipping, the sealing ring provided bythe instant invention substantially eliminates this problem. Theinterference fit between the sealing ring or rings and the annular capskirt portion provides enough frictional resistance to prevent thebacking off or unscrewing which might otherwise result.

In addition, the sealing ring and cooperating annular cap portion of theinvention overcomes an additional problem often encountered. When filledcontainers having either threaded or bayonet type caps are stacked inwarehouses or during shipping, especially those containing heavyliquids, the caps are pressed down tightly against the liners to thefull extent of any tolerance or possible vertical movement. This givesthe liners the undesirable set so that when the top pressure is removed,leakage may result. Because the horizontal seal provided according tothe invention is not affected by such vertical pressure, the resistanceto cap removal and secondary seal against leakage of a closure accordingto the invention remain effective.

What I claim is: j

l. A leak proof safety closure comprising a container and a cap, andsaid container having a bottom, a sidewall, a neck and an annularshoulder extending between said neck and said sidewall, and at least onelug recess in said container adjacent the periphery of said shoulder,said cap having a top, an inner wall depending from said top,cooperating means on said closure neck and said inner wall for retainingsaid cap in closed position on said container, at least one annularsealing ring on said container neck, said sealing ring having an outerdiameter fitting tightly within said inner cap wall when said cap is inclosed position, and an outer skirt depending from said top inconcentric relationship to said inner wall, said skirt including atleast one depending lug having a lower portion extending below thebottom of said inner wall and engageable in said lug recess.

2. A closure according to claim 1 and camming means on said shoulder forguiding said lug toward said lug recess.

3. A closure according to claim 1 wherein said cap includes twodiametrically opposed lugs depending from said skirt and said containershoulder has two opposed lug recesses.

4. A closure according to claim 1 and a resilient liner in the cap thatis engageable with the end of the container neck when said cap is inclosed position.

5. In a closure according to claim 1, the improvement comprising acircumferentially extending series of lug recesses in thecontainer-shoulder which are sequentially engaged by the locking lugwhen the cap is screwed more tightly onto the container neck.

6. A closure according to claim .1 in which there are a plurality ofspaced annular sealing rings on said container neck.

7. A closure according to claim 1 in which the annular sealing ring hasa sharp outer edge for establishing substantially a line contact withthe inner surface of said cap skirt.

8. A closure according to claim 1 inwhich the co operating means aremating threads.

9. A closure according to claim 1 in which the sealing ring is below thethreads on the container neck.

10. A leak proof safety closure comprising a container and a cap, saidcontainer having a bottom, a sidewall, a neck and an annular shoulderextending be-- tween said neck and said sidewall, at least one lugrecess in said container adjacent the periphery of said shoulder, saidcap having a top, a wall depending from said top, cooperating means onsaid closure neck and said wall for retaining said cap in' closedposition on said container, and at least one integral annular sealingring between said wall and said containerv neck, said sealing ringhaving an interference sealing fit when said cap is in its closedposition, said wall depending from said top and including at least onelug adjacent its lower edge engageable in said lug recess.

11. A closure according to claim 10, wherein said sealing ring isintegrally formed on said container neck.

1. A leak proof safety closure comprising a container and a cap, andsaid container having a bottom, a sidewall, a neck and an annularshoulder extending between said neck and said sidewall, and at least onelug recess in said container adjacent the periphery of said shoulder,said cap having a top, an inner wall depending from said top,cooperating means on said closure neck and said inner wall for retainingsaid cap in closed position on said container, at least one annularsealing ring on said container neck, said sealing ring having an outerdiameter fitting tightly within said inner cap wall when said cap is inclosed position, and an outer skirt depending from said top inconcentric relationship to said inner wall, said skirt including atleast one depending lug having a lower portion extending below thebottom of said inner wall and engageable in said lug recess.
 2. Aclosure according to claim 1 and camming means on said shoulder forguiding said lug toward said lug recess.
 3. A closure according to claim1 wherein said cap includes two diametrically opposed lugs dependingfrom said skirt and said container shoulder has two opposed lugrecesses.
 4. A closure according to claim 1 and a resilient liner in thecap that is engageable with the end of the container neck when said capis in closed position.
 5. In a closure according to claim 1, theimprovement comprising a circumferentially extending series of lugrecesses in the container shoulder which are sequentially engaged by thelocking lug when the cap is screwed more tightly onto the containerneck.
 6. A closure according to claim 1 in which there are a pluralityof spaced annular sealing rings on said container neck.
 7. A closureaccording to claim 1 in which the annular sealing ring has a sharp outeredge for establishing substantially a line contact with the innersurface of said cap skirt.
 8. A closure according to claim 1 in whichthe co-operating means are mating threads.
 9. A closure according toclaim 1 in which the sealing ring is below the threads on the containerneck.
 10. A leak proof safety closure comprising a container and a cap,said container having a bottom, a sidewall, a neck and an annularshoulder extending between said neck and said sidewall, at least one lugrecess in said container adjacent the periphery of said shoulder, saidcap having a top, a wall depending from said top, cooperating means onsaid closure neck and said wall for retaining said cap in closedposition on said container, and at least one integral annular sealingring between said wall and said container neck, said sealing ring havingan interference sealing fit when said cap is in its closed position,said wall dependiNg from said top and including at least one lugadjacent its lower edge engageable in said lug recess.
 11. A closureaccording to claim 10, wherein said sealing ring is integrally formed onsaid container neck.